British trio Dan Evans, Heather Watson and Aljaz Bedene all lost in the first round of the Miami Open.
World number 43 Evans was given a point penalty for swearing midway through the final set of his 7-5 0-6 6-3 loss to American qualifier Ernesto Escobedo.
Watson, who reached the fourth round last year, also lost to a qualifier, beaten 7-6 (7-4) 6-1 by Romania's Patricia Maria Tig.
The defeat means the Briton will drop from her current ranking of 108.
Bedene was trailing Germany's Jan-Lennard Struff 7-5 4-0 when he was forced to retire from his match.